// 拖拽的指令
const drag = {
  beforeMount(el: any, binding: any) {
    // 自定义属性，判断是否可拖拽
    if (!binding.value) return;
    // 获取自定义指令所在的dom元素
    const dialogHeaderEl = el.querySelector('.dialog_header');
    const dragDom = el.querySelector('.dialog_content');
    dialogHeaderEl.style.cssText += ';cursor:move;';
    // dragDom.style.cssText += ';bottom:0px;'

    // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
    const sty = (function () {
      if ((document.body as any).currentStyle) {
        // 在ie下兼容写法
        return (dom: any, attr: any) => dom.currentStyle[attr];
      }
      return (dom: any, attr: any) => getComputedStyle(dom, null)[attr];
    })();
    //判断元素移动还是被点击
    let isMove = false;

    dialogHeaderEl.onmousedown = (e: any) => {
      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - dialogHeaderEl.offsetLeft;
      const disY = e.clientY - dialogHeaderEl.offsetTop;
      const screenWidth = document.body.clientWidth; // body当前宽度
      const screenHeight = document.documentElement.clientHeight; // 可见区域高度(应为body高度，可某些环境下无法获取)

      console.log(dragDom, 'dragDomWidth');
      const dragDomWidth = dragDom.offsetWidth; // 对话框宽度
      const dragDomheight = dragDom.offsetHeight; // 对话框高度

      const minDragDomLeft = dragDom.offsetLeft;
      const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth;

      const minDragDomTop = dragDom.offsetTop;
      const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomheight;

      // 获取到的值带px 正则匹配替换
      let styL = sty(dragDom, 'left');
      // 为兼容ie
      if (styL === 'auto') styL = '0px';
      let styT = sty(dragDom, 'top');

      // console.log(styL)
      // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
      if (styL.includes('%')) {
        styL = +document.body.clientWidth * (+styL.replace(/%/g, '') / 100);
        styT = +document.body.clientHeight * (+styT.replace(/%/g, '') / 100);
      } else {
        styL = +styL.replace(/px/g, '');
        styT = +styT.replace(/px/g, '');
      }

      document.onmousemove = function (e) {
        // 通过事件委托，计算移动的距离
        let left = e.clientX - disX;
        let top = e.clientY - disY;
        // 边界处理
        if (-left > minDragDomLeft) {
          left = -minDragDomLeft;
        } else if (left > maxDragDomLeft) {
          left = maxDragDomLeft;
        }

        if (-top > minDragDomTop) {
          top = -minDragDomTop;
        } else if (top > maxDragDomTop) {
          top = maxDragDomTop;
        }
        // 移动当前元素
        isMove = true;
        dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`;
      };

      document.onmouseup = function (e: any) {
        document.onmousemove = null;
        document.onmouseup = null;
      };
      return false;
    };
    //元素被点击时执行的点击事件
    dialogHeaderEl.onclick = () => {
      if (isMove) {
        isMove = false;
        return;
      }
      window.history.back();
    };
  },
};
// 挂载，注册
const directives = {
  install: function (app: any) {
    app.directive('dialogDrag', drag);
  },
};
export default directives;

export { drag };
